But I think GBP, EUR, and CHF have the higher value than USD. How could you said that the value of the currencies has lost? And I think GBP is the most stable currency in the world. CMIIW
Yes. They were having a higher value, in a one-to-one denominational comparison. But this value has fallen, by a lot. The USD vs EUR exchange rate was like 1 = 1.4$ earlier. Now it is like 1 = 1.1$. The Euro has lost around 30% of its value against the Dollar.
And the one-to-one banknote exchange rates doesn't matter much. For example, the Latvian Lats is having an exchange rate of 1 LVL = $1.61. But you can't say that the Latvian Lats is a stronger currency when compared to the USD. Because the market cap of LVL can be measured in a few hundred million USD, while that of USD is in trillions of $$$.